Hybrid foundation Seefeldergasse
Assignment:
For the construction of a residential neighbourhood without basements the ground should be improved. Between the top soil and the medium densely bedded gravel there is a loosely bedded intermediate layer of silty fine sand to sandy silt to a depth of 2.6m. In order to prevent grain redistribution due to fluctuating groundwater level with its to be expected settling, an excavation and backfill of lean concrete to a depth of 2.8m was foreseen. An alternative was being looked for so as to shorten the construction time and to optimize the construction progress.
Solution:
The Hybrid-foundation „System TERRA-MIX“ was selected.
1st step:
Improving the silty fine sand and the same time respectively creating the work level with a layer strength of 45cm by means of milling a suitably with the ground harmonized binding agent into the ground. Evd>35MN/m2.
2nd step:
Impulse Compaction in several work steps and re-filling of the settling cones with binding agent improved soil.
3nd step:
Creating a frost-proof substitute base layer „System TERRA-MIX“ with a layer strength of 45cm by means of milling a suitably with the ground harmonized binding agent into the ground. This substitute layer serves as a load compensating layer above the compaction columns. Evd>70MN/m2
Results:
By using the Hybrid-foundation „System TERRA-MIX“ the use of resources could be minimized , the construction time be shortened and a foundation version of very high quality could be established.
